The Use of Fazadinium in Children - An Electro-Myographic Study

Abstract

Children (64) aged 6 mo. to 12 yr received fazadinium 0.75, 1.0 and 1.25 mg/kg and pancuronium 0.1 mg/kg in groups of 16 to compare the drugs'' effects. Neuromuscular transmission [NT] was evaluated electromyographically using train-of-4 stimuli. The times to 1st effect, maximum effect, 1st sign of recovery, reversal and full recovery after reversal were recorded; NT was monitored continuously until complete recovery was obtained. Duration of satisfactory clinical relaxation and NT when relaxation became inadequate were recorded. The speed, duration and depth of effect as well as the duration and degree of neuromuscular blockade increased significantly depending on dose. Fazadinium was potent, providing satisfactory relaxation in a dose of 1.0-1.25 mg/kg for operations of medium to long duration in children under light halothane anesthesia. When relaxation became inadequate NT still showed marked depression. Duration and degree of blockade of fazadinium and pancuronium were not age-dependent. In all groups the neuromuscular blockade was reversed easily. Apart from the speed of onset of action, pancuronium 0.1 mg/kg corresponded to a dose of fazadinium between 1.0 and 1.25 mg/kg. Train-of-4 ratio was more sensitive than single twitch as an index of the recovery of transmission during recovery and in the period after operation.